The subject matter disclosed herein generally relates to modulating furnaces, and in particular to a method and system for controlling an inducer in a modulating furnace.
Modulating furnaces operate through ranges of combustion airflow and gas rate in order to efficiently meet heat demand. Existing modulating furnaces run between 40% and 100% of total capacity based on heat demand and other variables. One challenge in operating a modulating furnace over a range of heating capacities is control of the inducer. The inducer draws air through the heat exchanger and sends the air out a vent. It is desirable to provide a smooth transition of inducer speed over a range of operating capacities without requiring additional components, such as pressure transducers.